Amino acid sequence requirements of laminin beta1 chain peptide B133 (DISTKYFQMSLE) for amyloid-like fibril formation, syndecan binding, and neurite outgrowth promotion.

Peptide B133 (DSITKYFQMSLE), derived from mouse laminin beta1 chain (residues 1298-1309), promotes cell attachment, neurite outgrowth, and amyloid-like fibril formation. Previously, we showed that the N-terminal Asp-deleted peptide B133a (SITKYFQMSLE) promotes integrin alpha2beta1-mediated cell attachment and spreading but does not form amyloid-like fibrils, and that the C-terminal Glu-deleted peptide B133g (DSITKYFQMSL) attaches cells without cell spreading and forms amyloid-like fibrils. In this study, we further investigated the amino acid sequence requirements of B133 for biological function using a set of truncated and Ala-substituted peptides. Attachment of cells to B133g was inhibited by only heparin, and Congo Red analysis indicated that the amyloid-like fibril formation activity of B133g was stronger than that of B133. Alanine scan analysis for the B133g peptide indicated that Asp and Ile residues are essential for cell attachment. Additionally, the N-terminal Asp residue was required for neurite outgrowth. Further, amyloid-like fibril formation required Asp and Ile residues. These data suggest that the amyloid-like fibril formation of B133g is required for cell attachment activity. We also evaluated the attachment of cells to the peptides using syndecan- and glypican-overexpressing cells. B133g attached to syndecan-overexpressing cells but not to glypican-overexpressing cells, suggesting that the amyloidogenic peptides promote syndecan-mediated cell attachment. These findings were useful for clarifying the mechanism of amyloid-like fibril formation and biological functions. The B133 peptide promotes amyloid-like fibril formation, syndecan-mediated cell attachment, and neurite outgrowth and has the potential for use as a biomaterial for tissue engineering.